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IIT Bombay develops technology for mechanical recycling of waste thermoplastic polymers to composites

Indigenous equipment called single screw extruder developed for mechanical recycling through melt-mixing of waste thermoplastic polymers and inorganic particulate fillers can help manufacture and characterize polymer composites that can be moulded to the required shape for making paver blocks, tiles, and bricks.

At present, commercially available melt-mixing equipment are not designed for handling waste thermoplastic polymers that are often adhered by contaminants, as the barrel and screw system are not robust enough.

IIT Bombay has developed an instrument named GolDN (pronounced as Golden) for melt-mixing of waste thermoplastic polymers and inorganic particulate fillers to manufacture polymer composites.

It can carry out melt mixing as a continuous process, particularly in laboratory conditions, to replicate the real-life conditions as compared to other conventionally available instruments. The researchers at the institute considered some key parameters such as compression ratio and clearance depth to facilitate efficient mixing of waste polymers and fillers.

The above technology, developed with the support of Department of Science and Technology (DST) through Waste Management Technologies, is now ready for commercialization for carrying out melt- mixing operations in a laboratory environment. It can bring down the cost of this instrument to INR 5 lakhs (by 6-8 times at least) by avoiding the complex design and operating tools and including the indigenous fabrication that are required.

The researchers have also developed a TGeosA for obtaining thermogravimetric analyses of the polymer composites obtained from the melt mixing instrument. The setup facilitates a sample size as high as 200 g that can incorporate the heterogeneity aspect of the materials being tested.

Further, a pilot-scale setup for manufacturing polymer composites has been indigenously fabricated. This setup consists of a shredder, a mixer cum preheater, and an extruder to obtain the fresh binder filler composite to shred the plastic waste, mix and preheat plastic waste and IBPs, and melt plastic waste along with IBPs followed by conveying at the end, respectively.

The technology developed by IIT Bombay in collaboration with Belagavi works of Hindalco Industries Ltd. (Industry collaborator) is at the TRL-09 and a field-scale plant has been set up.

Figure 3. Image of the tiles and Paver blocks created as a part of trails conducted on field scale setup


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